Abstract: A spacer assembly for restricting actuation of a hydraulic cylinder. The spacer assembly comprises a support bracket configured to be secured to the hydraulic cylinder. The spacer assembly additionally comprises a plurality of shims supported by the support bracket, whereby each of the shims is configured to be shifted between an unengaged position and an engaged position. When the shims are in the engaged position the shims are configured to restrict actuation of the hydraulic cylinder. The spacer assembly further comprises a shifting assembly configured to permit a group of at least two shims to be simultaneously shifted between the unengaged position and the engaged position.

Abstract: A reciprocating low-speed heavy-load hydraulic pump with a variable action area comprises a plurality of hydraulic cylinder units (3) and moving members (1, 2). Two ends of the hydraulic cylinder units (3) are separately connected with the moving members (1, 2) via mechanical structures. The moving members (1, 2) move relative to each other. The hydraulic cylinder unit (3) consists of a hydraulic cylinder (4), a reversing valve (5) and a one-way valve (6). The hydraulic cylinder (4), the reversing valve (5) and the one-way valve (6) are connected with each other via hydraulic pipelines. Based on different magnitudes of driving force, the hydraulic pump can proactively configure and form different combinations of hydraulic cylinder units, and further adjust the size of an equivalent action area.

Abstract: A hydraulic system is provided, having a pump, operably connected to a motor. It also comprises a controller-driven hydraulic actuator, operably connected to the pump and a hydraulic valve, operable to direct hydraulic fluid to and from either a rod side or a cylinder side of the hydraulic actuator. Rod and cylinder side pressures are pre-defined based on the instantaneous acceleration or deceleration required. Decelerating the hydraulic actuator could involve maintaining the current pressure in the meter-out side of the hydraulic actuator and decreasing the current pressure in the meter-in side by varying the speed of the pump. Deceleration of the hydraulic actuator could also include decreasing pressure on the meter-in side of the hydraulic actuator at a higher rate than on the meter-out side. Acceleration is achieved using a similar approach.

Abstract: In a fluid pressure cylinder, a piston is displaced in an axial direction under the action of a pressure fluid. A circular protrusion, which projects toward the piston along an axial direction of the cylinder tube, is formed on an inner end surface of a collar member constituting part of the fluid pressure cylinder, a concavity, which can be fitted externally over the circular protrusion, is formed on the piston, and an annular groove is formed on an inner circumferential edge of an end plate. By the piston coming into contact with the end plate, a pressure receiving chamber is formed between the piston and the annular groove, together with an opening of a second port on an inner side of the cylinder tube being closed to a maximum of 90%.

Abstract: An aircraft door actuator, including: a pneumatic cylinder for the opening of the door including a chamber into which a pressurized gas is injected via a first port, means for supplying the chamber of the cylinder with pressurized gas, via a supply pipe and said first port, means for setting the chamber to atmospheric pressure when the piston is in the position for opening the door, so as to allow said door to be moved into the closing position, including: a pressurized gas exhaust pipe a gate-valve means for guiding the opening of the gate-valve via the pressurized fluid located in the chamber when the door is in the opening position, so as to open the exhaust pipe in order to set said chamber of the cylinder to atmospheric pressure in a rapid manner once the door is open.

Abstract: A lifting mechanism is disclosed which is operated hydraulically and is configured to be mounted or used on a mobile working machine. The lifting mechanism or its hydraulics have a relieving pressure limiting valve which can be regulated as a function of the ground profile. For this purpose, a directly or indirectly measuring sensor arrangement is provided. Furthermore, a method is disclosed which serves for regulating a relieving pressure of a lifting mechanism of a mobile working machine. The method has the following steps (i) detection of the ground profile via a sensor arrangement, and (ii) limitation of the relieving pressure of a relieving line by setting an opening pressure of an electronically activatable proportional relieving pressure limiting valve via a control unit as a function of signals from the sensor arrangement.

Abstract: A pneumatic nailer includes a tool housing enclosing a cylinder with a reciprocating drive piston, and having a trigger and a workpiece contact element both connected to a trigger valve. A valve cap is mounted to the housing and includes a cycle valve and a dump valve, each valve reciprocating in a respective valve chamber. The dump valve controls drive pressure for the drive piston, the cycle valve controls the return of the dump valve to allow piston return. The valve cap and the valves are constructed and arranged such that the piston is returned to a start position independent of positions of the trigger or the workpiece contact element.

Abstract: A hydraulic arrangement for regulating a lifting mechanism (12) of an agricultural machine (10) is described. The hydraulic arrangement (16) comprises a hydraulic cylinder (24) having a chamber (50) capable of being acted upon by pressure, a proportionally adjustable inflow valve (22) which is connected on the outlet side via an inflow line (30) to the chamber (50) and which is connected on the inlet side to a hydraulic pump (18, 18?), a first outlet line (32) which makes a connection between the chamber (50) and a hydraulic tank (20), adjustment means (42, 44) for generating an adjustment signal for the hydraulic cylinder (24), and an electronic control unit (40).

Abstract: A hydraulic brake booster system. The hydraulic brake booster system includes a primary piston axially moveable within a bore of a cylinder, a booster chamber located rearwardly of the primary piston within the bore, an input rod extending within the booster chamber, a booster vent path in selective fluid communication with the booster chamber, and a seal member located between the forward face and the primary piston, the seal member in a fixed relationship with the input rod and configured to (i) seal the booster vent path from the booster chamber when the input rod is in a first position, and (ii) not seal the booster vent path from the booster chamber when the input rod is moved rearwardly within the booster chamber to a second position.

Abstract: A power steering device for a vehicle which is disposed in the transmission path between a steering handle and a steerable vehicle wheel, comprises a servo cylinder having two pressure chambers, which are separated by a working piston and are each connected to a pressure supply unit. A valve plunger, which seals a bypass channel between the pressure chambers, is movably disposed on the working piston. Furthermore, an adjustment bushing comprising an adjustment section is disposed in the servo cylinder, the valve plunger being moved against this section upon approaching an axial limit position, thereby opening the bypass channel. The adjustment bushing is clamped into the servo cylinder, yet held displaceably, wherein, on the adjustment bushing, a sealing section is provided, which is to be moved into a sealing position with the working piston so as to interrupt the flow connection between the pressure chambers.

Abstract: Hydraulic actuator as an element of a system for controlling an engine valve is presented. The actuator includes a fluidic actuation chamber, defined by an actuation piston that increases chamber volume as the actuation piston is urged away from a neutral. Chamber includes a high pressure fluid inlet and a fluid outlet. A fluidic actuator control chamber, defined by a control piston connected to the actuation piston that increases chamber volume as the actuation piston is urged away from neutral. A control fluid outlet is connected to a fluid control spool valve. The fluid outlet of the actuation chamber is fluidly connected to an inlet of the control valve. There is a valve actuation plunger operably connected to the actuation piston, and a drain outlet to maintain a fluidic backpressure to the actuator control chamber.

Abstract: The invention concerns a driving device, particularly a lifting device for a working vehicle, with a drive in the form of a hydraulic motor, the drive having a first connection and a second connection, a pump and a control valve arrangement between the drive and the pump. It is endeavoured to provide a simple way of extending the functionality of such lifting devices. For this purpose, the control valve arrangement can be switched from a first operating state, in which the motor is driven in a single-acting manner, to a second operating state, in which the motor is driven in a double-acting manner.

Abstract: A system by which the air exhausted from either end of a pneumatic cylinder is directed, by an arrangement of control valves, to external surge tanks of appropriate volume where it is compressed to produce a deceleration effect at the end of each stroke before being released to the atmosphere.

Abstract: An automatic depth control system is disclosed. The system includes a Console and remote Controller mounted in the tractor cab, power beyond Valving, and Depth Sensors, either ground contact or non-ground contact, mounted on the frame of the implement. The depth sensing system is provided to sense the actual penetration of an implement tool by determining the height of the implement frame above the ground. A circuit system is provided to receive the depth signal and to signal power beyond valving that will effect hydraulic corrections in order to maintain the select depth penetration. The Console includes an instrument panel having a toggle switch with AUTO, LOCK and MANUAL positions, an LED showing depth of tool penetration and a bargraph depicting variations from a desired depth and flashing lights on the bargraph to show depth corrections in process. The Console also includes a depth window in which no hydraulic correction would be made, a sensitivity switch, depth sensor switches and an UP/REPHASE switch.

Abstract: A method and an apparatus for controlling the function of all kinds of reciprocable power machines which are actuated by pneumatic, hydraulic of any other pressure fluid, irrespective if the machines are of rotary or axially operating type, in which the active power stroke is accomplished using full power of pressure fluid against a reciprocatable piston (2) in the active air pressure chamber (10, 12), and in which the reversing of the direction of operation is made by alternatingly supplying pressure fluid to the opposite air pressure chamber (12, 10) of the machine. A valve poppet (6) having several channels alternately places one of the pressure chambers (10, 12) of the reciprocatable fluid actuated machine (1, 2) under full pressure, builds up a certain counter pressure in a pressure chamber which is, at the actual moment, inactive, and evacuates the pressure from an inactive pressure chamber of the fluid actuated machine.

Abstract: A check valve for controlling a pneumatic threaded fastener-setting tool comprises a hollow cylinder housing connected between the tool and a pneumatic source for transmitting the air pressure therethrough, a retaining ring, a stopper member, a guider member, a slide and the springs sequentially disposed inside the housing. An actuator rod inserted into the tool pushes the slide moving inward for permitting the stopper member to close an air duct in order to interrupt the air fluid from going through thus to stop a shank of the tool from further extracting movement.

Abstract: An engine for driving a piston arrangement for pumping water from an inlet to an outlet at a higher level is disclosed. The engine includes a hollow housing having an inlet and an outlet between which liquid passes, the housing at least partly enclosing a chamber through which the liquid flows from the inlet to the outlet. A movable wall is mounted in the housing and partly defines the chamber. A valve is provided to open and close the outlet so that when it closes, liquid in the chamber is suddenly decelerated producing an increase in pressure in the chamber to force the wall to move to a direction so as to increase the volume of the chamber. After an initial increase in the pressure, the water relaxes and the pressure decreases to such an extent that a spring will open the valve and the spring returns the wall to the position of decreased volume in the chamber. Thus, the wall is caused to reciprocate under the influence of pressure of the liquid increasing and decreasing as the valve is opened and shut.

Abstract: A fluid apparatus includes a pneumatic cylinder having a main body, a piston, and a hollow rod. A ball screw shaft engaged with a ball nut fixed to the piston is rotatably and axially unmovably mounted in the cylinder and extends in the hollow rod. A magnetic brake for braking the ball screw shaft is fixed to an end portion of the main body of the cylinder. The number of revolutions of the ball screw shaft is detected and outputted in a signal form by a rotary encoder. A primary solenoid controlled valve reciprocates the piston by connecting a pressure source either to a first or second port of the cyliner, and secondary solenoid controlled valves connect a pressure source either to a first braking pressure port or to a second braking pressure port.

Abstract: A speed-reducing valve assembly is provided in an air passage through which compressed air is discharged when a pneumatic actuator is decelerated. The speed-reducing valve assembly comprises a three-way valve actuated by a signal generated when the actuator has reached the point where deceleration is started, a relief valve through which the compressed air in the passage is let out when the air pressure has reached the preset level, and a check valve that allows only the admission of compressed air into the same passage. The signal-actuated three-way valve brings the air passage of the actuator into communication with the passage in which the relief valve and check valve are provided. When the signal generated when the actuator has reached the deceleration starting point is fed to the speed-reducing valve assembly, the exhaust passage of the actuator communicates with the relief valve and check valve.

Abstract: Miniature engine operated by an expanding gaseous fluid, which comprises a cylinder (18), piston (20) and inlet valve (29), the upper part of the piston (20) cooperating with a radially expansible resilient diaphragm (28), which is secured to the piston (20) and performs momentarily a pneumatic seal-engagement function along the periphery of said cylinder (18) during the gaseous expansion phase.

Abstract: An impact tool for striking a tool such as a chisel includes a piston mounted in a cylinder. Upper, middle and lower chambers are formed therebetween. Pressure oil is fed into and discharged from the middle and lower chambers to reciprocate the piston in the cylinder under oil pressure. During a downward stroke of the piston, the oil pressure in the lower chamber is kept low. But just before it strikes a tool, the oil pressure in the lower chamber is adapted to increase so as to prevent what is called cavitation or prevent air bubbles mixed in the pressure oil in the lower chamber from growing suddenly owing to a sharp drop in the oil pressure which is caused by the rebound of the piston after striking the tool.

Abstract: A pilot valve assembly is provided which substantially eliminates stalling in air motors. The pilot valve assembly is located on one end over an air piston such that when the air piston hits the trip rod, the trip rod compresses a trip spring which is in turn compressed until the load of the force stored in this spring is sufficient to overcome the inlet air pressurizing the opposite side of the pilot valve and the main spring which also pre-loads the pilot valve. At this point, air is allowed to pass through the open pilot valve, allowing a spool valve to switch over and reverse the direction of the motor.

Abstract: Small-sized engine operated by an expanding gaseous fluid, which comprises a cylinder (18), a piston (20) and an inlet valve (38), the upper parts of the cylinder (18) and the piston (20) cooperating momentarily with a perforated (29) resilient membrane (28) circumferentially secured to the cylinder (18) and performing the functions of a pneumatic seal temporarily.

Abstract: Apparatus for controlling a plurality of moving members, e.g. the flaps in an installation for heating and ventilating or for air conditioning a motor vehicle, comprises single-acting actuators (46, 48) whose piston rods (50, 52) are connected to rotate the flaps about their respective axes (12, 14), with the actuators (46, 48) being fed from a pressurized fluid distributor (32) which includes moving elements which are respectively connected to control means and to each of the piston rods (50, 52), together with fluid flow servo control means for putting the displacement of one flap under the control of the displacement of another flap.

Abstract: The double-acting hydraulic cylinders of the lift system are connected in a master-slave series relationship. When the cylinders have been retracted to a predetermined extent, a control valve between the last slave and a primary selector valve of the system is mechanically closed responsive to the arrival of the cylinders at such retracted condition and, simultaneously, the master is prevented from further retraction by either mechanical means or another hydraulic control valve between the master and the primary selector valve. Thus, the cylinders and their interconnecting lines are cut off from inadvertent overcharging, as well as fluid escape, so that all cylinders remain uniformly extended with drift from their established positions. Several circuit arrangements are disclosed, including provision for bleeding off higher than necessary operating pressures tending to become trapped within the cylinders and their associated flow lines after the cylinders have reached the intended point of retraction.

Abstract: A hydraulic cylinder stroke limiter has a valve for controlling fluid flow from a port of the cylinder. A flexible hose has one end fixed to the valve housing and the other end movably supported at the rod end of the cylinder by a pivotal bracket. A cable extends through the hose and is anchored at one end with respect to the bracket and at the other end to a poppet movable to open to close the valve. A stop is mountable on the piston rod to engage the bracket, its movement being communicated by the cable to the poppet to close the valve and prevent further rod retraction.

Abstract: A hydraulic operating apparatus including an actuating cylinder having a piston arranged therein and moved by a fluid under high pressure further includes a control valve having only one metallic seal whether the piston is at its upper or lower positions. The control valve is operative to apply the fluid under high pressure to a pressure receiving surface of the piston on the opposite side of a piston rod to move the piston in a direction in which the piston rod extends from the piston and to discharge the fluid existent on the opposite side of the piston rod from the actuating cylinder to move the piston in a direction opposite the direction in which the piston rod extends from the piston.

Abstract: A device for the raising and lowering of a tilting cab of a road vehicle, with respect to the chassis of the vehicle on which the cab is pivoted, permits both lifting and lowering to take place under the control of a manual pump. The cab can also be left in a "floating" condition, when lowered, for the absorption of vibration which would otherwise be transmitted to it by the chassis during running, and in the "floating" condition, exceeding of a certain amplitude of relative movement between the cab and the chassis causes hydraulic clamping of the cab with respect to the chassis. A mechanical locking device may additionally be provided for locking the cab to the chassis in fully lowered condition, and the hydraulic system may permit acceleration of the downward movement of the cab, during lowering, for better engagement of such mechanical locking device.

Abstract: A manually operable position lock for a hydraulic actuator (10) adding a cylinder (20) and a piston rod (22) with a stop finger (61) for actuating a push rod (60) to close a valve (32) and prevent fluid egress from the cylinder. The lock includes a pivot bracket (110) carried by a push rod, a control lever (111) pivoted to the pivot bracket, a link (114) pivoted to the control lever and slidably receiving the push rod, and a helical spring (120) carried by the push rod and engaging one end of the link.

Abstract: An improved type of hydraulic control cartridge with mounting structure and accessorial safety device for installation within both ends of reciprocative pneumatic actuators to permit a safe increase in their speed of operation. The safety device automatically stops the actuator if the hydraulic cartridge malfunctions.

Abstract: A hydraulic control system is provided for a roof support unit of an underground mining installation. The roof support unit is provided with a roof cap supported by hydraulic props. The control system comprises a valve for controlling the supply of pressurized hydraulic fluid to the props, and an actuator for closing the valve when the props have been retracted by a predetermined amount.

Abstract: A defrost and water drain valve suitable for use with air cylinders, such as used to furnish power to material handling equipment, is connected to receive air from the exhaust side of the piston and direct this air against the inlet end of the cylinder and is constructed so that it can also automatically function to permit drainage of condensed water in the cylinder. The valve includes means to control flow to and from the exhaust side of the piston and the use of its features in a flow control valve and a check valve is also disclosed.

Abstract: A fluid pressure supply apparatus includes a fluid pressure source, a fluid supply circuit to receive fluid under pressure from the fluid pressure source, and a fluid return circuit. These circuits are to be coupled to an hydraulic motor through first and second fluid paths. The supply apparatus further includes first means to couple the fluid supply circuit to the first fluid path to cause the hydraulic motor to be operated by the fluid pressure in a predetermined sense, and second means simultaneously to couple the second fluid path either to the fluid supply circuit, to provide a regenerative coupling for the motor, or to a fluid return path. This latter coupling is initially to the second fluid path, the second means being arranged to transfer that coupling from the fluid supply circuit to the fluid return path during operation of the motor in the predetermined sense.

Abstract: The invention relates to a valve assembly adapted in conjunction with a valve actuator to provide positive control of the stroke of hydraulic cylinders. The valve is attached to a pressure port on the cylinder and the actuator assembly is positioned on the side of the cylinder and held by means of clamps. The stroke of the cylinder is limited when the actuator arm is clamped on the piston shaft at a distance shorter than the full stroke of the cylinder. In this condition as the shaft moves into the cylinder, the actuator arm contacts closure means within the valve thereby closing off the valve and preventing further retraction of the cylinder. The apparatus of the invention is adapted to be supplied in the kit form and can be readily attached, externally to any existing hydraulic actuator.

Abstract: A pneumatically buffered drive system is provided which quickly moves a movable member, such as a press safety curtain or press bolster, a predetermined length in three sequential speed stages to prevent maximum acceleration from occurring at the end of the predetermined length. The movable member is coupled to a differential pressure piston which is initially pressurized on only one side of the piston to initiate movement. After traversing approximately half the predetermined length both sides of the piston are pressurized to decelerate the piston during the member movement for approximately the next third of the predetermined length. The remaining length is traversed with the decelerating pressure being vented to positively finish the motion along the predetermined path. In vertical moving members having significant mass such as press safety curtains, a higher pressure is used to decelerate the piston than the pressure used to drive the piston.

Abstract: A fluid cylinder assembly includes a cylinder and a piston slidably disposed in the cylinder, the cylinder having a cylinder bore closed at both ends by end caps. One of the end caps is provided therein with a flow control valve assembly for controlling the fluid flow from the cylinder bore during a working stroke of the fluid cylinder assembly. The flow control valve assembly comprises a poppet valve having a pair of poppets on a valve rod and a spool valve movable in response to the operation of the poppet valve. The poppet valve is shiftable by a solenoid alternately energized and de-energized by an electric control circuit which is closed just before contact of a cutter on the piston rod with a workpiece.

Abstract: A brake actuator for a vehicle having air brakes is disclosed in which air pressure is expelled through the actuator upon release of the brakes in order to purge the latter of contaminants. The actuator includes a housing in which a piston reciprocates. Fluid pressure is admitted to the chamber defined between one side of the piston and the corresponding end of the housing in order to urge the latter in a brake actuating direction. The piston includes a passage extending therethrough to connect the chambers defined between opposite sides of the piston and the corresponding ends of the housing, and a shuttle valve carried within the passage in order to close the passage upon brake application and open the passage to permit fluid communication between the chambers upon brake release. An articulated guide rod is pivotally mounted on the end wall of the housing and extends into the piston to guide the shuttle valve during operation of the actuator.

Abstract: There is herein disclosed a lift control system for a press unloader having an extendable and retractable jaw means for gripping and removing a part from the die cavity of a press with pivotal frame means supporting the jaw means for pivotal movement to lift the part from the die cavity and interconnected air operated power cylinder means to sequentially extend the jaw means, grip the part, lift the part, and retract the jaw means.

Abstract: A stroke control mechanism for a hydraulic actuator having a piston and cylinder device including a blocking valve for selectively blocking fluid flow from one side of the actuator, the blocking valve consisting of a spring biased check valve mounted on one end of a valve stem and actuable by a control bar on the piston rod at the end of the stroke of the piston, the spring biased check valve being constructed to be opened by fluid pressure flowing to the extending side of the piston without movement of the valve stem so that creepage of the piston during its retracting movement resulting in contact between the valve stem and the actuating member will not prevent reversal of the piston.

Abstract: An adjustable stroke length fluid cylinder used to move agricultural or industrial machinery is disclosed. The cylinder is an enclosed unit having a movable piston therein which is attached to an axial piston rod secured to the load. A fluid valve directs the application of pressure fluid to either side of the piston to extend or retract the piston rod. One end of the cylinder houses a head unit containing an internal valve which is operated by a stop member positioned on the piston rod. The internal valve is effective to stop retraction of the piston rod when actuated by the stop member by blocking fluid flow through the cylinder. Subsequent extension of the piston rod automatically returns the internal valve to its open position.